From 6047f04a12d4fe2ca341dfe7c2d99063c2a738bf Mon Sep 17 00:00:00 2001
From: "Nicholas J. Kain" <nicholas@kain.us>
Date: Tue, 11 Jan 2022 22:16:44 -0500
Subject: [PATCH] Guard against carrier being spuriously set down.

Corrects a possible regression introduced by the previous patch.
---
 src/ndhc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/ndhc.c b/src/ndhc.c
index 3c7f967..0c468a0 100644
--- a/src/ndhc.c
+++ b/src/ndhc.c
@@ -313,7 +313,8 @@ static void do_ndhc_work(void)
         if (pfds[0].revents & POLLIN) {
             had_event = true;
             sev_nl = nl_event_get(&cs);
-            cs.carrier_up = (sev_nl == IFS_UP);
+            if (!cs.carrier_up)
+                cs.carrier_up = (sev_nl == IFS_UP);
         }
         if (pfds[0].revents & (POLLHUP|POLLERR|POLLRDHUP)) {
             suicide("nlfd closed unexpectedly");